1. Field of the Invention
This invention relates to an endoscope having a plurality of bending portions.
2. Description of the Related Art
Jpn. Pat. Appln. KOKAI Publication No. 2009-160211 has disclosed an endoscope which allows one of two knobs of an operation portion to be moved along the axial direction of the knobs so that the two knobs are interlocked or individually operable. When the two knobs are interlocked, first and second bending portions can be bent at the same time. When the two knobs are individually operable, the first bending portion and the second bending portion can be separately bent.
Jpn. Pat. Appln. KOKAI Publication No. 2010-201 has disclosed an endoscope including a first bending portion which vertically bends, and a second bending portion which horizontally bends together with the first bending portion. That is, if the first bending portion is bent, for example, upward, the second bending portion bends, for example, leftward at the same time.
When an endoscope including not only a first bending portion but also a second bending portion is used, it is generally possible to improve the performance of the insertion of an insertion portion into an insertion target such as a large intestine.
For example, when the insertion portion of the endoscope is inserted to the far side of the large intestine from the anus side, a surgeon generally holds and operates the insertion portion of the endoscope with the left hand, and firmly holds the insertion portion with the right hand to rotate the insertion portion around the axis or axially move the insertion portion. When the insertion portion is inserted in the large intestine to some degree, the surgeon preferably keeps holding the insertion portion without taking the right hand off the insertion portion to stabilize the position of the insertion portion while feeling the insertion into the large intestine.